spring boot——spring boot的基本配置——spring boot整合mybatis——本地实例运行——MyBatis动态SQL——MyBatis if标签——示例001...

水深无声 2024-03-30 15:12 28阅读 0赞

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pojo类：

package org.example.entity;
    
    public class MyUser
    {
        private int id;
        private String name;
        private int age;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
        @Override
        public String toString() {
            return "MyUser{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

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mapper文件：

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="org.example.mapper.UserMapper">
        <select id="findAll" resultType="org.example.entity.MyUser">
            select * from users
        </select>
    
        <insert id="saveUser" parameterType="org.example.entity.MyUser">
            insert into users(id,name,age) values(#{id},#{name},#{age})
        </insert>
    
        <insert id="saveUser2" parameterType="org.example.entity.MyUser">
            insert into users(id,name,age) values(#{id},#{name},#{age})
        </insert>
    
        <insert id="saveInsertUser" parameterType="org.example.entity.MyUser">
            <selectKey keyProperty="id" keyColumn="id" order="AFTER" resultType="int">
                SELECT LAST_INSERT_ID();
            </selectKey>
            insert into users(id,name,age) values(#{id},#{name},#{age})
        </insert>
    
        <update id="updateUser" parameterType="org.example.entity.MyUser">
            update users set name = #{name},age = #{age} where id = #{id}
        </update>
    
        <delete id="deleteUser" parameterType="java.lang.Integer">
            delete from users where id = #{id}
        </delete>
    
        <delete id="deleteUserByName" parameterType="java.lang.String">
            delete from users where name = #{name}
        </delete>
    
        <select id="findById" parameterType="java.lang.Integer" resultType="org.example.entity.MyUser">
            select * from USERs where id = #{id}
        </select>
    
        <select id="findByName" parameterType="java.lang.String" resultType="org.example.entity.MyUser">
            select * from USERs where name = #{name}
        </select>
    
        <select id="findByNameMf" parameterType="java.lang.String" resultType="org.example.entity.MyUser">
            select * from USERs where name like #{name};
        </select>
    
        <select id="findByNameMf2" parameterType="java.lang.String" resultType="org.example.entity.MyUser">
            select * from USERs where name like '%${value}%';
        </select>
    
        <select id="findTotal" resultType="int">
            select count(id) from USERs；
        </select>
    
        
        <select id="findUserByCondition" parameterType="org.example.entity.MyUser" resultType="org.example.entity.MyUser">
            select * from USERs where 1=1
            <if test="name != null">
                and name = #{name}
            </if>
            <if test="id != null">
                or id = #{id}
            </if>
            <if test="age != null">
                or age = #{age}
            </if>
        </select>
    
    </mapper>

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mapper接口文件：

package org.example.mapper;
    
    import org.example.entity.MyUser;
    import org.apache.ibatis.annotations.Mapper;
    import java.util.List;
    @Mapper
    public interface UserMapper
    {
        public List<MyUser> findAll();
    
        void saveUser(MyUser user);
    
        int saveUser2(MyUser user);
    
        int saveInsertUser(MyUser user);
    
        int updateUser(MyUser user);
    
        int deleteUser(Integer id);
    
        int deleteUserByName(String name);
    
        MyUser findById(Integer id);
    
        List<MyUser> findByName(String name);
    
        List<MyUser> findByNameMf(String name);
    
        List<MyUser> findByNameMf2(String name);
    
        int findTotal();
    
        /**
         *查询条件可能是id、用户名，年龄；也可能都有，也可能都没有
         */
        List<MyUser> findUserByCondition(MyUser user);
    
    }

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service接口：

package org.example.service;
    
    import org.example.entity.MyUser;
    import java.util.List;
    
    public interface UserService
    {
        List<MyUser> findAll();
    
        void saveUser(MyUser user);
    
        int saveUser2(MyUser user);
    
        int saveInsertUser(MyUser user);
    
        int updateUser(MyUser user);
    
        int deleteUser(Integer id);
    
        int deleteUserByName(String name);
    
        MyUser findById(Integer id);
    
        List<MyUser> findByName(String name);
    
        List<MyUser> findByNameMf(String name);
    
        List<MyUser> findByNameMf2(String name);
    
        int findTotal();
    
        List<MyUser> findUserByCondition(MyUser user);
    
    }

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实现service接口：

package org.example.service.Impl;
    
    import org.example.entity.MyUser;
    import org.example.mapper.UserMapper;
    import org.example.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import java.util.List;
    
    @Service
    public class UserServiceImpl implements UserService
    {
        @Autowired
        UserMapper userMapper;
    
        @Override
        public List<MyUser> findAll()
        {
            return userMapper.findAll();
        }
    
        @Override
        public void saveUser(MyUser user)
        {
            userMapper.saveUser(user);
        }
    
        public int saveUser2(MyUser user)
        {
            return userMapper.saveUser2(user);
        }
    
        public int saveInsertUser(MyUser user)
        {
    
            return userMapper.saveInsertUser(user);
        }
    
        public int updateUser(MyUser user)
        {
            return userMapper.updateUser(user);
        }
    
    
        public int deleteUser(Integer id)
        {
            return userMapper.deleteUser(id);
        }
    
        public int deleteUserByName(String name)
        {
            return userMapper.deleteUserByName(name);
        }
    
        public MyUser findById(Integer id)
        {
            return userMapper.findById(id);
        }
    
        public List<MyUser> findByName(String name)
        {
            return userMapper.findByName(name);
        }
    
        public List<MyUser> findByNameMf(String name)
        {
            return userMapper.findByNameMf(name);
        }
    
        public List<MyUser> findByNameMf2(String name)
        {
            return userMapper.findByNameMf2(name);
        }
    
        public int findTotal()
        {
            return userMapper.findTotal();
        }
    
        public List<MyUser> findUserByCondition(MyUser user)
        {
    
            return userMapper.findUserByCondition(user);
        }
    }

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控制器：

package org.example.controller;
    
    import java.util.List;
    import org.example.entity.MyUser;
    import org.example.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class MyUserController
    {
        @Autowired
        private UserService userService;
    
        @GetMapping(value = "/1")
        public List<MyUser> home1()
        {
            // 查询所有网站
            List<MyUser> users = userService.findAll();
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
            return users;
        }
    
        @GetMapping(value = "/2")
        public void home2()
        {
            MyUser user2 = new MyUser();
            user2.setName("TTT");
            user2.setAge(7878);
    
            userService.saveUser(user2);
    
        }
    
        @GetMapping(value = "/3")
        public int home3()
        {
            MyUser user2 = new MyUser();
            user2.setName("RRR");
            user2.setAge(6666);
    
            int a = userService.saveUser2(user2);
    
            System.out.println(a);
    
            return a;
    
        }
    
        @GetMapping(value = "/4")
        public int home4()
        {
            MyUser user2 = new MyUser();
            user2.setName("ccc");
            user2.setAge(321123);
    
            userService.saveInsertUser(user2);
    
            int a = user2.getId();
    
            System.out.println(a);
    
            System.out.println(user2);
    
            return a;
    
        }
    
        @GetMapping(value = "/5")
        public int updateUser()
        {
            MyUser user2 = new MyUser();
            user2.setId(1013);
            user2.setName("sprint-boot-1013");
            user2.setAge(199999);
    
            int a = userService.updateUser(user2);
    
            System.out.println(a);
    
            return a;
    
        }
    
    
        @GetMapping(value = "/6")
        public int deleteUser()
        {
            int a = userService.deleteUser(1012);
    
            System.out.println(a);
    
            return a;
    
        }
    
        @GetMapping(value = "/7")
        public int deleteUserByName()
        {
            int a = userService.deleteUserByName("sprint-boot-1013");
    
            System.out.println(a);
    
            return a;
    
        }
    
        @GetMapping(value = "/8")
        public void findById()
        {
            MyUser user001 = userService.findById(1011);
    
            System.out.println(user001);
    
        }
    
        @GetMapping(value = "/9")
        public List<MyUser> findByName()
        {
            List<MyUser> users= userService.findByName("aaa");
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
            return users;
    
        }
    
        @GetMapping(value = "/10")
        public List<MyUser> findByNameMf()
        {
            List<MyUser> users= userService.findByNameMf("%ae%");
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
            return users;
    
        }
    
    
        @GetMapping(value = "/11")
        public List<MyUser> findByNameMf2()
        {
            List<MyUser> users= userService.findByNameMf2("ae");
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
            return users;
    
        }
    
        @GetMapping(value = "/12")
        public int findTotal()
        {
            int a = userService.findTotal();
    
            return a;
    
        }
    
    
        @GetMapping(value = "/13")
        public List<MyUser> findUserByCondition()
        {
            MyUser user2 = new MyUser();
            user2.setName("aaa");
            user2.setAge(111821);
    
    
            List<MyUser> users= userService.findUserByCondition(user2);
    
            for (MyUser user : users)
            {
                System.out.println(user.getId()+"  "+user.getName()+"  "+user.getAge());
            }
    
    
            return users;
    
        }
    
    }

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执行前：

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执行：

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[68bce122c29f3c08835d8e0596567fab.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/b6ae0a4e60bc405393da13e4a9515688.png
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[3b8137dc027ace4c0537abd4a2d20fde.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/f5dc0332a680446d9402ff12992d4ef5.png
[440b4ddd8ee107815fd12c3751e21814.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/568fc25e72134c0889295ec61194f208.png
[865783d5d49000e8834831205e2aa259.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/8c4529eeb5504ae59626aed8fe8d5f54.png
[087d2a354f3573ed4834de18bef6bf76.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/0c0896ac11bf4b1e94ea790e5479d604.png
[915ea04c07dc29fdce37ffef6a2a9808.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/f28eb78cb8ce424eb1fe7177ce9deaca.png